Process for fixing a rotor winding

ABSTRACT

A process for fixing a rotor winding, which is hooked to connection lugs of commutator lamellas of a commutator in the vicinity between the connection lugs and winding heads that are embodied on the end face of the rotor body. In order to simplify the process, a shrink sleeve is placed over the commutator of the completed rotor and is slid onto the winding heads until the connection lugs and the connection wires of the rotor winding that extend to the connection lugs are covered. The mechanically fixed shrink sleeve is homogeneously heated with hot air while the rotor rotates so that after cooling, the shrink sleeve shrinks onto the connection lugs and connection wires as well as onto parts of the winding heads.

PRIOR ART

The invention is based on a process for fixing a rotor winding, which ishooked to connection lugs or hooks of commutator lamellas of acommutator and is contained in a rotor body that is non-rotatablysupported on a common rotor shaft with the commutator, in the vicinitybetween the connection lugs or hooks and winding heads that are embodiedon the end face of the rotor head.

With rotors for commutator or collector machines, the individual,insulated winding wires of the rotor or armature winding are insertedinto axial grooves disposed offset from one another on the circumferenceof the rotor body, which is embodied as a laminated stack of sheets,wherein the end faces of the winding wires, which are wound intoseparate winding coils, protrude as a so-called winding heads from thetwo end faces of the rotor body. The separate connection wires to thewinding coils are conveyed to connection lugs embodied on the separatecommutator lamellas and are attached there by means of winding aroundthe connection lugs using different winding techniques and by bendingthe connection lugs while simultaneously carrying out an ultrasonicwelding. An exemplary embodiment for a so-called hook collector of thiskind and for the embodiment of the so-called hooking technique whenfixing the winding connection wires to the collector hooks is describedin WO 90/04864 A1 (FIG. 11).

So that no vibrational fractures are produced in the rotor windingduring operation and in particular during the usually required hardvibration testing of the rotor, the region of the rotor winding thatincludes the connection winding wires is fixed between the connectionlugs in a different manner, e.g. by means of a molded mass or by meansof tying with or without enameled wire.

ADVANTAGES OF THE INVENTION

The process according to the invention for fixing the rotor winding inthe region between the connection lugs and the winding heads of therotor winding has the advantage that on the one hand, existingmanufacturing processes and techniques can be used and on the otherhand, only one additional part is required which can be shrink-fittedwith a low degree of stress on the rotor and the rotor winding.

Advantageous improvements and updates of the process disclosed arepossible by means of the measures taken hereinafter.

BRIEF DESCRIPTION OF THE DRAWING

The process according to the invention is explained in detail in thesubsequent description in conjunction with an exemplary embodiment of arotor for a commutator machine shown in the drawing.

FIG. 1 is a perspective detail view of a completed rotor with a rotorshaft, rotor body, rotor winding, and commutator, as well as a shrinksleeve to be slid onto the commutator,

FIG. 2 is a perspective representation of the rotor in FIG. 1 after theshrink sleeve has been slid on.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

The armature or rotor 10, which is depicted in perspective fashion inFIGS. 1 and 2 and is for a commutator or collector machine, has a rotorbody 11 that is embodied as a laminated stack of sheets and a collectoror commutator 12, which are both non-rotatably supported on a commonrotor shaft 13. The rotor body 11 has axial grooves 14 disposeddistributed over the circumference, into which an armature or rotorwinding 15 is wound. The separate, insulated winding wires of the rotorwinding 15 are thereby inserted into the axial grooves 14 in a number oflocations and constitute separate winding coils that are connected in anelectrically conductive manner to the individual commutator lamellas 121of the commutator 12. The commutator lamellas 121 are disposed in theusual fashion next to one another on the circumference of an insulationmaterial body 123 non-rotatably supported on the rotor shaft 13, with aninsulating gap between them, and extend over the entire axial length ofthe insulation material body.

For the electrical connection of the rotor winding 15 to the commutator12, the individual commutator lamellas 121 are provided with connectionlugs 122, also called collector hooks, which are preferably embodied asone piece. On the end face of the commutator lamellas 121 orientedtoward the rotor body 11, the connection lugs 122 are angled away fromthis rotor body 11 and are bent over in the direction toward thecommutator lamellas 121 so that the individual connection lugs 122enclose a small, acute angle with their commutator lamellas 121.Connection wires 152 of the rotor winding 15 leading from the individualwinding coils of the rotor winding 15 to the connection lugs 121 areguided around the connection wires 152 in different hooking techniques,wherein they can wind around the respective connection lugs 122 once ora number of times and can be mechanically and electrically fastened tothe connection lugs 122, preferably by means of an ultrasonic weldingprocess.

The connection wires 152 extending in the region between the windingheads 151 and the connection lugs 122 must be fixed so that no windingfractures occur in the rotor winding 15 during operation and inparticular, during the usually required hard vibration testing forcommutator machines used in vehicle construction. Moreover, this fixingcounteracts centrifugal forces at higher speeds. In order to fix thiswinding region of the rotor winding 15, in the completed rotor 10 thatis described above and shown in FIG. 1, a shrink sleeve 16 is placedover the commutator 12 and slid onto the winding heads 151 of the rotorwinding 15 until the connection lugs 122 and the connection wires 152extending from the connection lugs 122 to the winding heads 151 arecompletely covered. The shrink sleeve 16 is mechanically fixed in itsposition, the rotor 10 is set into rotation, and the shrink sleeve 16 ishomogeneously heated with hot air. Preferably, a hot air jet produced bymeans of a hot air blower is used for the heating. As a result of thehomogenous heating, the shrink sleeve 16 shrinks and comes to restagainst the connection wires 152 in the region of the winding heads 151and connection lugs 122. Then, the shrink sleeve 16 cools and hardens.The connection wires 152 are therefore mechanically fixed and securedagainst centrifugal forces.

In the exemplary embodiment of FIG. 1, the shrink sleeve 16 is producedas an individual sleeve of a predetermined length. However, the shrinksleeve 16 can also be cut to length from an endless tube withappropriate dimensions. The shrink sleeve 16 is comprised for example ofVITON VS 15105-Bn.

The foregoing relates to a preferred exemplary embodiment of theinvention, it being understood that other variants and embodimentsthereof are possible within the spirit and scope of the invention, thelatter being defined by the appended claims.

We claim:
 1. A process for fixing a rotor winding (15), which is hooked to connection lugs (122) of commutator lamellas (121) of a commutator (12) and is contained in a rotor body (11) that is non-rotatably supported with the commutator (12) on a common rotor shaft (13), in a vicinity between the connection lugs (122) and winding heads (151) that are embodied on an end face of the rotor body (11), the process comprising: placing a shrink sleeve (16) over the commutator (12) of a completed rotor (10) with the rotor body (11), commutator (12), and rotor winding (15); sliding the shrink sleeve onto the winding heads (151) until the connection lugs (122) and connection wires (152) of the rotor winding (15) that extend to the connection lugs (122) are covered; and homogeneously heating the shrink sleeve (16) with hot air while the rotor (10) rotates to mechanically fix the shrink sleeve in place.
 2. The process according to claim 1, in which the shrink sleeve (16) is cut to length from an endless tube before being slid over the winding heads.
 3. The process according to claim 2, in which the shrinkage sleeve is produced as an individual sleeve of a predetermined length.
 4. The process according to one of claim 3, in which a hot air blower is used to produce the hot air.
 5. The process according to one of claim 2, in which a hot air blower is used to produce the hot air.
 6. The process according to one of claim 1, in which a hot air blower is used to produce the hot air. 